In communications systems, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications system is deployed.
For example, for future generations of mobile communications systems frequency bands at many different carrier frequencies could be needed. For example, low such frequency bands could be needed to achieve sufficient network coverage for wireless devices and higher frequency bands (e.g. at millimeter wavelengths (mmW), i.e. near and above 30 GHz) could be needed to reach required network capacity. In general terms, at high frequencies the propagation properties of the radio channel are more challenging and beamforming both at the access node of the network and at the wireless devices might be required to reach a sufficient link budget.
The wireless devices could implement beamforming by means of analog beamforming, digital beamforming, or hybrid beamforming. Each implementation has its advantages and disadvantages. A digital beamforming implementation is the most flexible implementation of the three but also the costliest due to the large number of required radio chains and baseband chains. An analog beamforming implementation is the least flexible but cheaper to manufacture due to a reduced number of radio chains and baseband chains compared to the digital beamforming implementation. A hybrid beamforming implementation is a compromise between the analog and the digital beamforming implementations. As the skilled person understands, depending on cost and performance requirements of different wireless devices, different implementations will be needed.
Different antenna architectures for different frequency bands are being discussed for wireless devices. At high frequency bands (e.g. above 15 GHz) something called “panels” of antenna arrays are being discussed. These panels of antenna array may be uniform linear/rectangular arrays (ULAs/URAs), for example steered by using analog phase shifters. In order to get coverage from different directions, multiple panels of antenna array can be mounted on different sides of the wireless devices. Unless specifically stated, the terms antenna array and panels will hereinafter be used interchangeably.
For wireless devices the incoming signals can arrive from all different directions, hence it could be beneficial to have an antenna configuration at the wireless device which has the possibility to generate omnidirectional-like coverage in addition to high gain narrow directional beams. For example, if the wireless device rotates quickly it could be difficult to maintain narrow beam communication with the radio access network node serving the wireless devices, and hence a more robust omnidirectional coverage would temporarily be preferred at the wireless device.
FIG. 1 schematically illustrates a wireless device 200′ comprising an example architecture of an analog antenna array 130a′ that can be used to generate a large variety of beamwidths. The analog antenna array 130a′ has four single polarized antenna elements 160a operatively connected to an analog distribution network 150a with one phase shifter and switch per antenna element. In turn the analog distribution network 150a is operatively connected to a single baseband (BB) chain 140a. A further antenna array 130b′ with single polarized antenna elements 160a and being operatively connected to a further baseband chain 140b via its own analog distribution network 150b could be provided in order to enable communication using orthogonal polarization.
By switching off all antenna elements 160a but one, it is possible to generate a beam with a large beamwidth (same as the antenna element beamwidth). Also, by switching off different number of antenna elements 160a it is possible to create a large variety of different beamwidths. This architecture hence gives a high flexibility in shaping the beam of the analog antenna array 130a. 
However, when switching off one or several antenna elements 160a of the analog antenna array 130a′, part of the received and/or transmitted signal power will be lost during the combination/splitting of the signals. Designing to low loss switch network allowing for one or more antennas to be disconnected may be possible but the design will be very complex, see for example document U.S. Pat. No. 6,323,742B1 for one such example. In addition to the complexity/loss issue applicable for both reception and transmission there is also a loss in available out power during transmission in case of distributed power amplifiers.
Hence, there is still a need for improved beamforming at a wireless device.